I have a data structure of like this.

Now i want to extract from product collection. i am already able to get its fields but don't known how to extract sub collections. Here is my code to extract product collection's field

useEffect(() => {
    async function fetchData() {
      const conditional_fetch = query(
        collection(db, "products"),
        where("active", "==", true)
      );
      const querySnapshot = await getDocs(conditional_fetch);
      const products = [];
      querySnapshot.forEach((doc) => {
        products[doc.id] = doc.data();
      });
      setProducts(products);
    }
    fetchData();

CodePudding user response：

You would have to make separate requests for each products prices sub-collection. So you could try something like this:

async function fetchData() {
  // 1. Fetching products
  const conditional_fetch = query(
    collection(db, "products"),
    where("active", "==", true)
  );

  const querySnapshot = await getDocs(conditional_fetch);
  const products = [];

  // 2. For each product, fetching documents from prices sub-collection
  for (const doc of querySnapshot.docs) {
    const prices = await getDocs(
      collection(doc.ref, "prices", "timestamp", "desc")
    );
    products.push({
      id: doc.id,
      ...doc.data(),
      prices: prices.docs.map(p => p.data())
    });
  }
  setProducts(products);
}